Driving assistance device and driving assistance system

ABSTRACT

A driving assistance device according to an embodiment includes: a target setting unit configured to set a stop target; an acquisition unit configured to acquire a position of a vehicle; and an output information control unit configured to control a display unit to display a first image that instructs a driver to stop the vehicle in a first form when the vehicle is located within a region including the stop target and display the first image in a second form different from the first form when the vehicle is located outside the region.

TECHNICAL FIELD

Embodiments of the present invention relate to a driving assistancedevice and a driving assistance system.

BACKGROUND ART

Some vehicles are mounted with an assistance device configured to assistparking and other driving situations. For example, the assistance deviceguides the vehicle to a target position. When the vehicle arrives at thetarget position, the assistance device instructs a driver to stop thevehicle by voice, for example.

Patent Document 1: Japanese Patent Application Publication No.2012-76483

DISCLOSURE OF INVENTION Problem to be Solved by the Invention

The driver recognizes an instruction from the assistance device, andfollows the instruction to perform various kinds of operations, such asstopping the vehicle and changing gears. If an instruction is made bythe assistance device suddenly, it may take time for the driver toperform the instructed operation.

Means for Solving Problem

A driving assistance device according to an embodiment, includes: atarget setting unit configured to set a stop target; an acquisition unitconfigured to acquire a position of a vehicle; and an output informationcontrol unit configured to control a display unit to display a firstimage that instructs a driver to stop the vehicle in a first form whenthe vehicle is located within a region including the stop target anddisplay the first image in a second form different from the first formwhen the vehicle is located outside the region. This configurationenables, for example, a driver to know in advance that the vehicle needsto be stopped.

In the driving assistance device according to an embodiment, the outputinformation control unit controls the display unit to display a secondimage that changes in accordance with the position of the vehicle. Thisconfiguration enables, for example, the driver to recognize a distanceto the stop target by the second image.

In the driving assistance device according to an embodiment, the secondimage indicates a direction corresponding to a travel direction of thevehicle, and the output information control unit controls the displayunit to dispose the first image in the direction indicated by the secondimage with respect to the second image. This configuration enables, forexample, the driver to more intuitively recognize the distance to thestop target by the second image.

In the driving assistance device according to an embodiment, the stoptarget includes a first target and a second target that is provided in amiddle of a path for guiding the vehicle to the first target, the firstimage includes a first mark and a second mark different from the firstmark, and the output information control unit controls the display unitto display the first mark when the vehicle travels toward the firsttarget and display the second mark when the vehicle travels toward thesecond target. This configuration enables, for example, the driver toknow in advance that the vehicle needs to be moved to the first targetafter the vehicle is stopped at the second target.

Furthermore, the output information control unit controls the displayunit to display the second image in the first form when the vehicle islocated within the region and display the second image in the secondform different from the first form when the vehicle is located outsidethe region. This configuration enables, for example, the driver to moreclearly recognize that the vehicle is located within the regionincluding the stop target.

Furthermore, the output information control unit controls the displayunit to display the first image or the second image brightly in thefirst form and display the first image or the second image darkly in thesecond form. This configuration enables, for example, the driver to moreclearly recognize that the vehicle is located within the regionincluding the stop target.

A driving assistance system according to an embodiment includes: atarget setting unit configured to set a stop target; an acquisition unitconfigured to acquire a position of a vehicle; and a display unitconfigured to display a first image that instructs a driver to stop thevehicle in a first form when the vehicle is located within a regionincluding the stop target and display the first image in a second formdifferent from the first form when the vehicle is located outside theregion. This configuration enables, for example, the driver to know inadvance that the vehicle needs to be stopped.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exemplary perspective view illustrating a vehicle with avehicle interior partially seen through, according to an embodiment;

FIG. 2 is an exemplary plan view (overhead view) of the vehicleaccording to the embodiment;

FIG. 3 is a view of an example of a dashboard of the vehicle as viewedfrom behind the vehicle, according to the embodiment;

FIG. 4 is an exemplary block diagram of a configuration of a parkingassistance system according to the embodiment;

FIG. 5 is an exemplary block diagram of a configuration of an ECU in theparking assistance system according to the embodiment;

FIG. 6 is an exemplary flowchart of a procedure of parking assistanceprocessing by a parking assistance unit according to the embodiment;

FIG. 7 is an exemplary diagram illustrating an example of a screen of adisplay device according to the embodiment;

FIG. 8 is an exemplary flowchart illustrating an example of a procedureof instruction screen display processing by an output informationcontrol unit according to the embodiment;

FIG. 9 is an exemplary diagram schematically illustrating a movementpath of the vehicle created by a path calculation unit according to theembodiment;

FIG. 10 is an exemplary diagram illustrating an example of the screen ofthe display device, which is displayed when the vehicle is located at astop target, according to the embodiment;

FIG. 11 is an exemplary diagram illustrating an example of the screen ofthe display device, which is displayed when the vehicle arrives at astop target for a turning position by forward movement, according to theembodiment;

FIG. 12 is an exemplary diagram illustrating an example of the screen ofthe display device, which is displayed when the vehicle travels toward astop target for a parking completed position, according to theembodiment; and

FIG. 13 is an exemplary diagram illustrating an example of the screen ofthe display device, which is displayed when the vehicle arrives at thestop target at the parking completed position, according to theembodiment.

BEST MODES FOR CARRYING OUT THE INVENTION

Exemplary embodiments of the present invention are disclosed below.Configurations in the following embodiments and actions, results, andeffects obtained by the configurations are illustrative. The presentinvention can also be implemented by other configurations than thosedisclosed in the following embodiments, and can provide at least one ofvarious kinds of effects based on fundamental configurations and theirsecondary effects.

A vehicle 1 according to the present embodiment may be, for example, anautomobile that uses an internal combustion engine (not illustrated) asa drive source, that is, an internal combustion engine automobile, anautomobile that uses a motor (not illustrated) as a drive source, thatis, an electric automobile or a fuel cell automobile, a hybridautomobile that uses both an internal combustion engine and a motor asdrive sources, or an automobile including another drive source. Thevehicle 1 can mount various kinds of transmission devices thereon, andcan mount thereon various kinds of devices such as systems andcomponents necessary for driving an internal combustion engine and amotor. The systems, number, and layout of devices related to driving ofwheels 3 in the vehicle 1 can be variously set.

As exemplified in FIG. 1, a vehicle body 2 constitutes a vehicleinterior 2 a where occupants (not illustrated) ride. In the vehicleinterior 2 a, a steering unit 4, an acceleration operation unit 5, abraking operation unit 6, a gear shift operation unit 7, and other suchunits are provided so as to face a seat 2 b for a driver as an occupant.The steering unit 4 is, for example, a steering wheel that protrudesfrom a dashboard 24. The acceleration operation unit 5 is, for example,an accelerator pedal located at the feet of the driver. The brakingoperation unit 6 is, for example, a brake pedal located at the feet ofthe driver. The gear shift operation unit 7 is, for example, a shiftlever that protrudes from a center console. The steering unit 4, theacceleration operation unit 5, the braking operation unit 6, the gearshift operation unit 7, and other such units are not limited to theabove.

In the vehicle interior 2 a, a display device 8 as a display output unitand a voice output device 9 as a voice output unit are provided. Thedisplay device 8 is, for example, a liquid crystal display (LCD) or anorganic electroluminescent display (OELD). The voice output device 9 is,for example, a speaker. The display device 8 is covered with atransparent operation input unit 10, such as a touch panel. Occupantscan view images displayed on a display screen of the display device 8through the operation input unit 10. The occupants can execute operationinputs by operating the operation input unit 10 by touching, pushing,and moving with their fingers at positions corresponding to the imagesdisplayed on the display screen of the display device 8. The displaydevice 8, the voice output device 9, the operation input unit 10, andother such units are provided to, for example, a monitor device 11located at a central portion of the dashboard 24 in the vehicle widthdirection, that is, in the horizontal direction. The monitor device 11may include an operation input unit (not illustrated), such as a switch,a dial, a joystick, and a push button. Another voice output device (notillustrated) may be provided at a position in the vehicle interior 2 adifferent from the position of the monitor device 11. Voice may beoutput from the other voice output device and the voice output device 9included in the monitor device 11. The monitor device 11 may be usedalso as a navigation system or an audio system.

In the vehicle interior 2 a, a display device 12 different from thedisplay device 8 is provided. As exemplified in FIG. 3, for example, thedisplay device 12 is provided to an instrument panel unit 25 in thedashboard 24, and is located between a speed display unit 25 a and anrpm display unit 25 b at substantially the center of the instrumentpanel unit 25. The size of a screen 12 a of the display device 12 issmaller than the size of a screen 8 a of the display device 8. Imagesrepresenting information on parking assistance for the vehicle 1 may bemainly displayed on the display device 12. The amount of informationdisplayed on the display device 12 may be smaller than the amount ofinformation displayed on the display device 8. The display device 12 is,for example, an LCD or an OELD. Information displayed on the displaydevice 12 may be displayed on the display device 8 also.

As exemplified in FIGS. 1 and 2, the vehicle 1 is, for example, afour-wheel automobile, and has two right and left front wheels 3F andtwo right and left rear wheels 3R. The four wheels 3 are each turnable.As exemplified in FIG. 4, the vehicle 1 includes a steering system 13configured to steer at least two wheels 3. The steering system 13includes an actuator 13 a and a torque sensor 13 b. The steering system13 is electrically controlled by an electronic control unit (ECU) 14 andthe like to operate the actuator 13 a. The steering system 13 is, forexample, an electric power steering system or a steer-by-wire (SBW)system. The steering system 13 adds torque, that is, assist torque, tothe steering unit 4 by the actuator 13 a to compensate for steeringforce, and turns the wheel 3 by the actuator 13 a. In this case, theactuator 13 a may turn one wheel 3 or may turn a plurality of wheels 3.For example, the torque sensor 13 b detects torque applied by the driverto the steering unit 4.

As exemplified in FIG. 2, the vehicle body 2 is provided with, forexample, four image pickup units 15 a to 15 d as a plurality of imagepickup units 15. The image pickup unit 15 is, for example, a digitalcamera having imaging elements incorporated therein, such as chargecoupled devices (CCDs) and CMOS image sensors (CISs). The image pickupunit 15 can output moving image data at a predetermined frame rate. Eachimage pickup unit 15 includes a wide angle lens or a fisheye lens, andcan photograph a range of 140° to 190° in the horizontal direction, forexample. The optical axis of the image pickup unit 15 is set to beobliquely downward. The image pickup unit 15 thus sequentiallyphotographs the road surface where the vehicle 1 is movable and externalenvironments around the vehicle body 2 including a region where thevehicle 1 can be parked, and outputs the photographed images asphotographed image data.

For example, the image pickup unit 15 a is located at a rear end portion2 e of the vehicle body 2 and provided at a wall portion below a door 2h of a rear trunk. For example, the image pickup unit 15 b is located ata right end portion 2 f of the vehicle body 2 and provided to a rightdoor mirror 2 g. For example, the image pickup unit 15 c is located onthe front side of the vehicle body 2, that is, at a front end portion 2c in the vehicle longitudinal direction and provided to a front bumperor the like. For example, the image pickup unit 15 d is located on theleft side of the vehicle body 2, that is, at a left end portion 2 d inthe vehicle width direction and provided to a door mirror 2 g as aleft-side protrusion. The ECU 14 can execute calculation processing andimage processing on the basis of image data obtained by the image pickupunits 15, thereby generating images with a wider angle of view andvirtual overhead images as seen from above the vehicle 1. The overheadimage can be referred to also as “plan image”.

On the basis of images from the image pickup units 15, the ECU 14identifies partition lines and the like indicated on the road surfacearound the vehicle 1 to detect (extract) a parking section indicated bythe partition lines and the like.

As exemplified in FIGS. 1 and 2, the vehicle body 2 is provided with,for example, four distance measurement units 16 a to 16 d and eightdistance measurement units 17 a to 17 h as a plurality of distancemeasurement units 16 and 17. The distance measurement units 16 and 17are, for example, sonars configured to emit ultrasound and capture itsreflected waves. The sonar can be referred to also as “sonar sensor” or“ultrasound detector”. The ECU 14 can detect the presence/absence of anobject such as an obstacle located around the vehicle 1 and measure thedistance to the object on the basis of detection results of the distancemeasurement units 16 and 17. Specifically, the distance measurementunits 16 and 17 are an example of a detection unit configured to detectan object. For example, the distance measurement units 17 may be used todetect an object at a relatively short distance, and for example, thedistance measurement units 16 may be used to detect an object at arelatively long distance farther than that for the distance measurementunits 17. For example, the distance measurement units 17 may be used todetect objects ahead and behind the vehicle 1, and the distancemeasurement units 16 may be used to detect objects on the sides of thevehicle 1.

As exemplified in FIG. 4, in a parking assistance system 100, the ECU14, the monitor device 11, the steering system 13, and the distancemeasurement units 16 and 17 as well as a brake system 18, a steeringangle sensor 19, an accelerator sensor 20, a shift sensor 21, a wheelspeed sensor 22, and the like are electrically connected to one anothervia an in-vehicle network 23 as an electric communication line. Thein-vehicle network 23 is configured as, for example, a controller areanetwork (CAN). The ECU 14 can control the steering system 13, the brakesystem 18, and other such systems by transmitting control signals viathe in-vehicle network 23. The ECU 14 can receive, via the in-vehiclenetwork 23, detection results of the torque sensor 13 b, a brake sensor18 b, the steering angle sensor 19, the distance measurement units 16,the distance measurement units 17, the accelerator sensor 20, the shiftsensor 21, the wheel speed sensor 22, and other such systems andoperation signals of the operation input unit 10 and other such units.

The ECU 14 includes, for example, a central processing unit (CPU) 14 a,a read only memory (ROM) 14 b, a random access memory (RAM) 14 c, adisplay control unit 14 d, a voice control unit 14 e, and a solid statedrive (SSD, flash memory) 14 f. For example, the CPU 14 a can executeimage processing on images to be displayed on the display devices 8 and12 and various kinds of calculation processing and control, such asdetermining a movement target position of the vehicle 1, calculating amovement path of the vehicle 1, determining the presence/absence of aninterference with an object, performing automatic control of the vehicle1, and releasing the automatic control. The CPU 14 a can read a computerprogram installed and stored in a non-volatile storage device such asthe ROM 14 b, and execute calculation processing in accordance with thecomputer program. The RAM 14 c temporarily stores therein various kindsof data used for the calculation by the CPU 14 a. The display controlunit 14 d mainly executes image processing that uses image data obtainedfrom the image pickup units 15, the processing of combining image datato be displayed on the display device 8, and other processing among thecalculation processing in the ECU 14. The voice control unit 14 e mainlyprocesses voice data output from the voice output device 9 among thecalculation processing in the ECU 14. The SSD 14 f is a rewritablenon-volatile storage unit, and can store data therein even when the ECU14 is powered off. The CPU 14 a, the ROM 14 b, the RAM 14 c, and thelike may be integrated in the same package. The ECU 14 may be configuredto use another logic calculation processor or logic circuit such as adigital signal processor (DSP) in place of the CPU 14 a. A hard diskdrive (HDD) may be provided in place of the SSD 14 f. The SSD 14 f andthe HDD may be provided separately from the ECU 14.

The brake system 18 is, for example, an anti-lock brake system (ABS)configured to prevent the locking of the brake, an electronic stabilitycontrol (ESC) configured to prevent the skidding of the vehicle 1 duringcornering, and an electric brake system configured to enhance brakeforce (execute brake assist), and a brake-by-wire (BBW). The brakesystem 18 applies braking force to the wheels 3 and thus the vehicle 1via an actuator 18 a. The brake system 18 can detect the locking of thebrake, the spinning of the wheel 3, and the sign of the skidding on thebasis of the rotation difference between the right and left wheels 3,and execute various kinds of control. The brake sensor 18 b is, forexample, a sensor configured to detect the position of a movable portionin the braking operation unit 6. The brake sensor 18 b can detect theposition of a brake pedal that is the movable portion. The brake sensor18 b includes a displacement sensor.

The steering angle sensor 19 is, for example, a sensor configured todetect the steering amount of the steering unit 4 such as a steeringwheel. For example, the steering angle sensor 19 is configured by a Hallelement. The ECU 14 acquires the steering amount of the steering unit 4by the driver, the steering amount of each wheel 3 for automaticsteering, or the like from the steering angle sensor 19, and executesvarious kinds of control. The steering angle sensor 19 detects arotational angle of a rotating portion included in the steering unit 4.The steering angle sensor 19 is an example of an angle sensor.

The accelerator sensor 20 is, for example, a sensor configured to detectthe position of a movable portion in the acceleration operation unit 5.The accelerator sensor 20 can detect the position of an acceleratorpedal that is the movable portion. The accelerator sensor 20 includes adisplacement sensor.

The shift sensor 21 is, for example, a sensor configured to detect theposition of a movable portion in the gear shift operation unit 7. Theshift sensor 21 can detect the position of a lever, an arm, a button, orthe like that is the movable portion. The shift sensor 21 may include adisplacement sensor, or may be configured as a switch.

The wheel speed sensor 22 is a sensor configured to detect the rotationamount of the wheel 3 or revolutions of the wheel 3 per unit time. Thewheel speed sensor 22 outputs a wheel speed pulse count representing thedetected rpm as a sensor value. For example, the wheel speed sensor 22may be configured by a Hall element. The ECU 14 calculates the movementamount of the vehicle 1 and the like on the basis of the sensor valueacquired from the wheel speed sensor 22, and executes various kinds ofcontrol. The wheel speed sensor 22 may be provided in the brake system18. In this case, the ECU 14 acquires the detection result of the wheelspeed sensor 22 via the brake system 18.

The configurations, arrangement, and electrical connection forms ofvarious kinds of sensors and actuators described above are illustrative,and can be variously set (changed).

Next, the configuration of a parking assistance unit 140 implemented inthe ECU 14 is described. As illustrated in FIG. 5, the parkingassistance unit 140 includes a data acquisition unit 141, an obstacledetection unit 142, a parking section detection unit 143, a candidateposition setting unit 144, a target position determination unit 145, anoutput information control unit 146, a path calculation unit 147, aguidance control unit 148, and other units. The ECU 14 further includesa storage unit 149.

Each configuration in the parking assistance unit 140 illustrated inFIG. 5 is implemented when the CPU 14 a configured as the ECU 14 in FIG.4 executes a parking assistance program stored in the ROM 14 b, forexample. Specifically, the parking assistance unit 140 implements thedata acquisition unit 141, the obstacle detection unit 142, the parkingsection detection unit 143, the candidate position setting unit 144, thetarget position determination unit 145, the output information controlunit 146, the path calculation unit 147, the guidance control unit 148,and other units by execution the parking assistance program stored inthe ROM 14 b. Each of the units may be implemented by hardware. Thestorage unit 149 is implemented by, for example, the RAM 14 c or the SSD14 f.

The data acquisition unit 141 acquires various kinds of information,such as detection results of the sensors and the distance measurementunits 16 and 17, image data obtained by the image pickup units 15, andsignals of operation inputs from the operation input unit 10, anoperation unit 14 g, and other units. The operation unit 14 g is, forexample, a push button or a switch. The obstacle detection unit 142detects an obstacle on the basis of the information acquired by the dataacquisition unit 141. The parking section detection unit 143 detects aparking section on the basis of the information acquired by the dataacquisition unit 141. The candidate position setting unit 144 setscandidate positions for a movement target position of the vehicle 1. Thetarget position determination unit 145 determines the movement targetposition of the vehicle 1. The output information control unit 146determines information output from the display devices 12 and 8, thevoice output device 9, and other devices and the output form or the likeof the information. The path calculation unit 147 calculates a movementpath to the movement target position of the vehicle 1. The guidancecontrol unit 148 controls each unit in the vehicle 1 so that the vehicle1 moves to the movement target position along the movement path. Thestorage unit 149 stores therein data used for the calculation by the ECU14 or data calculated by the calculation by the ECU 14.

Next, an example of parking assistance processing performed by theparking assistance unit 140 according to the present embodiment isschematically described. The parking assistance processing describedbelow is illustrative, and may be partially omitted or changed. FIG. 6is a flowchart illustrating an example of a procedure of the parkingassistance processing by the parking assistance unit 140.

First, while the vehicle 1 is moving, the parking assistance unit 140detects vehicles stopped (stopped vehicles), obstacles such as curbs,and partition lines around the vehicle 1 (S100). For example, theobstacle detection unit 142 detects stopped vehicles and obstacles onthe basis of the detection results of the distance measurement units 16and 17 and the image data obtained by the image pickup units 15, whichare acquired by the data acquisition unit 141. The parking sectiondetection unit 143 detects a parking section on the basis of thedetected stopped vehicles, obstacles, partition lines, and the like. Thedetection of obstacles and the like may be performed constantly, or maybe performed, for example, when the speed of the vehicle 1 falls below avalue set in advance. The detection of obstacles and the like may bestarted after the driver operates the operation unit 14g.

Next, the parking assistance unit 140 determines a movement targetposition of the vehicle 1 (S200). For example, the candidate positionsetting unit 144 sets at least one candidate position on the basis ofthe detected stopped vehicles and the like and the detected parkingsection. The target position determination unit 145 determines at leastone movement target position of the vehicle 1 from the candidateposition.

Next, the parking assistance unit 140 creates a movement path of thevehicle 1 (S300). For example, the path calculation unit 147 creates atleast one movement path to the determined movement target position. Forexample, the path calculation unit 147 creates respective movement pathsfor moving the vehicle 1 to the movement target position by forwardparking, perpendicular parking, and parallel parking.

Next, the parking assistance unit 140 receives an operation input aboutselection and determination of a parking assistance function (S400). Forexample, when the driver operates the operation unit 14 g, the outputinformation control unit 146 that has acquired an input signal of theoperation via the data acquisition unit 141 displays a screen forselecting the parking assistance function on the screens 12 a and 8 a ofthe display devices 12 and 8. For example, the driver selects any one ofthe parking assistance functions of forward parking, perpendicularparking, and parallel parking. The parking assistance functions are notlimited to forward parking, perpendicular parking, and parallel parking,and include, for example, a function of assisting departure from aparking space to a driving lane. When the driver determines the parkingassistance function, the determined parking assistance function isstarted.

Next, the parking assistance unit 140 performs guidance control of thevehicle 1 on the basis of the selected parking assistance function(S500). For example, the guidance control unit 148 controls the steeringsystem 13 on the basis of the parking assistance function selected bythe driver to automatically steer the wheels 3, thereby assisting theparking of the vehicle 1 (automatic steering). The driver operates theacceleration operation unit 5, the braking operation unit 6, and thegear shift operation unit 7, thereby moving the vehicle 1 to themovement target position along the movement path corresponding to theselected parking assistance function. When the distance between thevehicle 1 and the movement target position becomes a predetermined valueor less, the guidance control is finished. The guidance control isfinished (cancelled) also when a predetermined operation is performed bythe steering unit 4, the acceleration operation unit 5, the brakingoperation unit 6, or the gear shift operation unit 7. During theguidance control, the target position determination unit 145 and thepath calculation unit 147 may reset the movement target position of thevehicle 1 and the movement path of the vehicle 1 in accordance with thesituation.

The guidance control unit 148 may automatically operate the accelerationoperation unit 5, the braking operation unit 6, and the gear shiftoperation unit 7 in addition to the steering system 13, therebyassisting the parking of the vehicle 1 (automatic controlling). Theparking assistance unit 140 may display the movement target position andthe movement path on the display device 12 when the vehicle 1 is movedfor parking, thereby assisting the parking by the driving by the driver(steering guidance).

In the parking assistance processing described above, for example, thetarget position determination unit 145 may determine the movement targetposition without using the candidate position set by the candidateposition setting unit 144. The parking assistance unit 140 may determinethe movement target position and create the movement path (S200, S300)after receiving an operation input about the selection and determinationof the parking assistance function (S400).

FIG. 7 is a diagram illustrating an example of the screen 12 a of thedisplay device 12. While the guidance control unit 148 controls eachunit in the vehicle 1, the output information control unit 146 controlsthe display device 12 by the display control unit 14 d in FIG. 3 todisplay an instruction screen 200 as illustrated in FIG. 7 on the screen12 a. For example, the instruction screen 200 displays the state of theparking assistance system 100 and an instruction to the driver.

The instruction screen 200 includes, for example, a vehicle symbol 201,a first display region 202, a state symbol 203, an instruction mark 204,an indicator 205, and a second display region 206. The instruction mark204 is an example of a first image. The indicator 205 is an example of asecond image.

The vehicle symbol 201 includes a vehicle state display portion 201 aand an obstacle display portion 201 b. The vehicle state display portion201 a schematically indicates the vehicle 1. The vehicle state displayportion 201 a may further display the position of the movable portion inthe gear shift operation unit 7. For example, when the movable portionin the gear shift operation unit 7 is shifted into the R-range, thevehicle state display portion 201 a displays a character “R” asillustrated in FIG. 7. The obstacle display portion 201 b is disposedaround the vehicle state display portion 201 a. When the distancemeasurement units 16 a to 16 d and the distance measurement units 17 ato 17 h detect an obstacle, for example, a part of the obstacle displayportion 201 b located in the corresponding direction is displayedbrightly to notify the driver of the presence of the obstacle in thecorresponding direction.

The first display region 202 displays character information representingthe state of the parking assistance system 100. For example, whenintelligent parking assist (IPA) in the parking assistance system 100 isin operation, the first display region 202 displays characterinformation that “IPA IN OPERATION” as illustrated in FIG. 7. Thecharacter information displayed in the first display region 202 is notlimited thereto.

The state symbol 203 represents the state of the parking assistancesystem 100. For example, when the guidance control unit 148 controls thesteering system 13 to automatically operate the steering unit 4, thestate symbol 203 indicating that the steering unit 4 is automaticallyoperated is displayed on the instruction screen 200. The state symbol203 is not limited thereto.

The instruction mark 204 is an image that instructs the driver to stopthe vehicle. A plurality of kinds of images are prepared as theinstruction mark 204. For example, the instruction screen 200 in FIG. 7displays a temporary stop mark 204 a as the instruction mark 204. Thetemporary stop mark 204 a is an example of a second mark.

The output information control unit 146 displays the instruction mark204 brightly or darkly. The display form in which the instruction mark204 is displayed brightly is an example of a first form. The displayform in which the instruction mark 204 is displayed darkly is an exampleof a second form.

The output information control unit 146 displays the instruction mark204 brightly when the vehicle 1 is located within a stop regionincluding a stop target described later. In contrast, the outputinformation control unit 146 displays the instruction mark 204 darklywhen the vehicle 1 is located outside the stop region. For example, thechroma of the instruction mark 204 when the vehicle 1 is located withinthe stop region is higher (brighter) than the chroma of the instructionmark 204 when the vehicle 1 is located outside the stop region. Withoutbeing limited to the chroma, the output information control unit 146 maychange the luminance or hue of the instruction mark 204.

The first form and the second form are not limited to the above. Forexample, the output information control unit 146 may display theinstruction mark 204 with an enlarged scale when the vehicle 1 islocated within the stop region, and display the instruction mark 204with a reduced scale when the vehicle 1 is located outside the stopregion.

The indicator 205 schematically represents the distance between thevehicle 1 and the stop target. For example, the indicator 205 ispartitioned into a plurality of sections displayed brightly or darkly.The output information control unit 146 increases or decreases thenumber of sections displayed brightly and the number of sectionsdisplayed darkly in the indicator 205 in accordance with the distancebetween the vehicle 1 and the stop target. In other words, the indicator205 changes in accordance with the position of the vehicle 1.

The indicator 205 further indicates the direction corresponding to thetravel direction of the vehicle 1. A plurality of kinds of images areprepared as the indicator 205. For example, the instruction screen 200in FIG. 7 displays a reverse indicator 205 a as the indicator 205. Theindicator 205 has a distal end portion 205 b that indicates thedirection, and the distal end portion 205 b of the reverse indicator 205a is directed downward in the instruction screen 200. The indicator 205indicates the direction corresponding to the travel direction of thevehicle 1 also by the direction in which the number of the sectionsdisplayed brightly or darkly is increased or decreased.

The instruction mark 204 is located in the direction indicated by theindicator 205 with respect to the indicator 205. For example, on theinstruction screen 200 in FIG. 7, the instruction mark 204 is locatedbelow the indicator 205.

The second display region 206 displays character information. Forexample, the character information in the second display region 206represents an operation that the driver needs to perform. For example,when the driver is required to move the vehicle 1 backward, the seconddisplay region 206 displays character information that “MOVE BACKWARD”as illustrated in FIG. 7. The character information displayed in thesecond display region 206 is not limited thereto.

Next, an example of instruction screen display processing performed bythe output information control unit 146 to display the instructionscreen 200 on the screen 12 a of the display device 12 is described.FIG. 8 is a flowchart illustrating an example of a procedure of theinstruction screen display processing performed by the outputinformation control unit 146.

First, the output information control unit 146 acquires a movementtarget position of the vehicle 1 from the target position determinationunit 145, and acquires a movement path to the movement target positionof the vehicle 1 from the path calculation unit 147 (S501). The pathcalculation unit 147 may create a movement path involving turning. Thepath calculation unit 147 sets, in such a movement path, a plurality ofpositions (turning positions) at which the vehicle 1 needs to be stoppedin addition to the movement target position (parking completedposition). Specifically, the turning positions are provided in themiddle of a movement path for guiding the vehicle 1 to the parkingcompleted position. In the following description, the parking completedposition and the turning position are sometimes referred to as “stoptargets”.

Next, the output information control unit 146 generates an instructionscreen 200, and displays the instruction screen 200 on the screen 12 aof the display device 12 by the display control unit 14 d (S502). Forexample, when the next stop target is a turning position, the outputinformation control unit 146 generates an instruction screen 200 thatincludes the temporary stop mark 204 a as the instruction mark 204. Whenthe vehicle 1 travels toward the next stop target by reverse movement,the output information control unit 146 generates the instruction screen200 that includes the reverse indicator 205 a as the indicator 205. Theoutput information control unit 146 further generates the second displayregion 206 that displays character information giving an instruction ofoperation to the driver.

Next, the output information control unit 146 compares the distancebetween the stop target and the vehicle 1 with a plurality of thresholds(S503). For example, the guidance control unit 148 calculates theposition of the vehicle 1 on the basis of the detection results of thedistance measurement units 16 and 17 acquired by the data acquisitionunit 141. In other words, the guidance control unit 148 acquires theposition of the vehicle 1. Specifically, the guidance control unit 148is an example of an acquisition unit. The guidance control unit 148 isnot limited thereto, and may calculate the position of the vehicle 1 onthe basis of the detection result of the wheel speed sensor 22. Theguidance control unit 148 further calculates the distance between thevehicle 1 and the stop target on the basis of the position of thevehicle 1.

The output information control unit 146 acquires the distance betweenthe stop target and the vehicle 1 from the guidance control unit 148.The output information control unit 146 further acquires a plurality ofthresholds that are stored in the storage unit 149 in advance. Theoutput information control unit 146 compares the distance between thestop target and the vehicle 1 with the thresholds.

If the output information control unit 146 determines that the distancebetween the stop target and the vehicle 1 falls below at least onethreshold (Yes at S503), the output information control unit 146 rendersthe indicator 205 again (S504). For example, the output informationcontrol unit 146 increases or decreases the number of sections displayedbrightly and the number of sections displayed darkly in the indicator205 in accordance with the threshold below which the distance betweenthe stop target and the vehicle 1 falls. After the output informationcontrol unit 146 renders the indicator 205 again, the output informationcontrol unit 146 returns to the comparison of the distance between thestop target and the vehicle 1 and a threshold (S503).

The output information control unit 146 stores the threshold below whichthe distance between the stop target and the vehicle 1 falls in thestorage unit 149. If the distance between the stop target and thevehicle 1 falls below a new threshold (Yes at S503), the outputinformation control unit 146 renders the indicator 205 again (S504).However, even if the distance between the stop target and the vehicle 1falls below the threshold again below which the distance has fallen, theoutput information control unit 146 does not render the indicator 205again (No at S503).

If the output information control unit 146 determines that the distancebetween the stop target and the vehicle 1 does not fall below a newthreshold (No at S503), the output information control unit 146determines whether the vehicle 1 is located in a stop region (S505).FIG. 9 is a diagram schematically illustrating a movement path 500 ofthe vehicle 1 created by the path calculation unit 147. As illustratedin FIG. 9, the path calculation unit 147 sets a stop target P (parkingcompleted position or turning position) and a stop region 501 includingthe stop target P in the movement path 500. Specifically, the pathcalculation unit 147 is an example of a target setting unit.

The stop region 501 is a region set around the stop target P.Specifically, the stop region 501 is set around the parking completedposition and is also set around the turning position. The stop target Pas the parking completed position is an example of a first target. Thestop target P as the turning position is an example of a second target.The stop target P as the turning position is provided in the middle of amovement path for guiding the vehicle 1 to the stop target P as theparking completed position.

Each stop region 501 includes a stop target region 502 and a stopavailable region 503. The stop target region 502 can be referred to as“first region”. The stop available region 503 can be referred to as“second region”.

The stop target region 502 is a region where the vehicle 1 needs to bestopped in order to be parked along the originally calculated movementpath 500. For example, the stop target region 502 is set in apredetermined range around the stop target P. The size of the stoptarget region 502 in the present embodiment is substantially the same asthe size of the vehicle 1. The stop target region 502 is not limitedthereto.

The stop available region 503 is set in a predetermined range around(ahead and behind) the stop target region 502. In other words, the stopavailable region 503 is a region outside the stop target region 502. Inthe case where the stop target P is a turning position, when the vehicle1 is stopped in the stop available region 503, the path calculation unit147 determines a new movement path 500 again. The new movement path 500may be a movement path involving turning. As described above, the stopavailable region 503 is a position from which the vehicle 1 can beguided to the parking completed position along a movement path 500different from the already set movement path 500. The stop availableregion 503 is not limited thereto.

The output information control unit 146 acquires the distance betweenthe stop target P and the vehicle 1 from the guidance control unit 148,and determines whether the vehicle 1 is located in the stop region 501.If the output information control unit 146 determines that the vehicle 1is not located in the stop region 501 (No at S505), the outputinformation control unit 146 returns to the comparison of the distancebetween the stop target P and the vehicle 1 with a threshold (S503).

If the output information control unit 146 determines that the vehicle 1is located in the stop region 501 (Yes at S505), the output informationcontrol unit 146 determines whether the vehicle 1 is located in the stoptarget region 502 (S506). The output information control unit 146acquires the distance between the stop target P and the vehicle 1 fromthe guidance control unit 148, and determines whether the vehicle 1 islocated in the stop target region 502.

FIG. 10 is a diagram illustrating an example of the screen 12 a of thedisplay device 12, which is displayed when the vehicle 1 is located inthe stop region 501. If the output information control unit 146determines that the vehicle 1 is located in the stop target region 502(Yes at S506), the output information control unit 146 displays theinstruction mark 204 on the screen 12 a of the display device 12brightly in red (with increased tone) (S507). The display form in whichthe instruction mark 204 is displayed brightly in red is an example of afirst form. The first form is not limited thereto.

In contrast, if the output information control unit 146 determines thatthe vehicle 1 is not located in the stop target region 502 (No at S506),the output information control unit 146 displays the instruction mark204 on the screen 12 a of the display device 12 brightly in orange(S508). In other words, if the output information control unit 146determines that the vehicle 1 is located in the stop available region503, the output information control unit 146 displays the instructionmark 204 brightly in orange. The display form in which the instructionmark 204 is displayed brightly in orange is an example of the firstform. For example, the output information control unit 146 may blink theinstruction mark 204.

If the vehicle 1 is located outside the stop region 501 (No at S505),the output information control unit 146 displays the instruction mark204 on the screen 12 a of the display device 12 darkly (with reducedtone). The display form in which the instruction mark 204 is displayeddarkly is an example of a second form. Specifically, the outputinformation control unit 146 displays the instruction mark 204 even whenthe vehicle 1 is located outside the stop region 501.

As described above, the output information control unit 146 displays theinstruction mark 204 brightly when the vehicle 1 is located within thestop region 501 including the stop target P, and displays theinstruction mark 204 darkly when the vehicle 1 is located outside thestop region 501. The output information control unit 146 displays theinstruction mark 204 such that the display form of the instruction mark204 when the vehicle 1 is located in the stop target region 502 and thedisplay form of the instruction mark 204 when the vehicle 1 is locatedin the stop available region 503 are different from each other.

Furthermore, the output information control unit 146 changes thecharacter information in the second display region 206 when the vehicleenters the stop region 501. For example, the output information controlunit 146 changes the character information in the second display region206 to “STOP VEHICLE”. The output information control unit 146 maycontrol the voice control unit 14 e such that the voice output device 9outputs sound effects and voice.

Furthermore, the output information control unit 146 displays allsections in the indicator 205 darkly when the vehicle 1 is locatedwithin the stop region 501. The display form in which all sections aredisplayed darkly is an example of the second form. The outputinformation control unit 146 displays at least one section in theindicator 205 brightly when the vehicle 1 is located outside the stopregion 501. The display form in which at least one section is displayedlightly is an example of the first form.

If the output information control unit 146 displays the instruction mark204 brightly in red or orange (S507, S508), the output informationcontrol unit 146 determines whether the vehicle 1 is stopped (S509). Forexample, the output information control unit 146 determines whether thevehicle 1 is stopped on the basis of the detection result of the wheelspeed sensor 22 acquired by the data acquisition unit 141.

If the output information control unit 146 determines that the vehicle 1is not stopped (No at S509), the output information control unit 146returns to the determination whether the vehicle 1 is located in thestop target region 502 (S506). In contrast, if the output informationcontrol unit 146 determines that the vehicle 1 is stopped (Yes at S509),the output information control unit 146 changes the characterinformation in the second display region 206 (S510). For example, whenthe vehicle 1 is stopped in the stop region 501 including the stoptarget P as a turning position, the output information control unit 146displays character information that gives an instruction of operationfor moving the vehicle 1 to the next movement path 500 in the seconddisplay region 206.

When the output information control unit 146 changes the characterinformation in the second display region 206, the display of theinstruction screen 200 generated by the output information control unit146 is finished. For example, when the next stop target P is furtherpresent after the vehicle has arrived at the stop region 501, the outputinformation control unit 146 generates and displays a new instructionscreen 200 for guiding the vehicle 1 to the stop target P.

A plurality of other examples of the screen 12 a of the display device12 are described below. FIG. 11 is a diagram illustrating an example ofthe screen 12 a of the display device 12, which is displayed when thevehicle 1 arrives at a stop target P as a turning position by forwardmovement. As illustrated in FIG. 11, when the vehicle 1 moves toward thestop target P as the turning position by forward movement, the outputinformation control unit 146 displays a forward indicator 205 c as theindicator 205. A distal end portion 205 b of the forward indicator 205 cis directed upward in the instruction screen 200.

The output information control unit 146 displays the temporary stop mark204 a because the vehicle 1 travels to the stop target P as the turningposition. The output information control unit 146 displays the temporarystop mark 204 a above the indicator 205.

When the vehicle 1 that has arrived at the stop region 501 including thestop target P as the turning position by forward movement is stopped,for example, the output information control unit 146 displays aninstruction screen 200 as illustrated in FIG. 11 on the screen 12 a ofthe display device 12. On the instruction screen 200 in FIG. 11, allsections in the indicator 205 are displayed darkly. The instruction mark204 is displayed brightly in red or orange.

The vehicle 1 that has arrived at the stop region 501 including the stoptarget P as the turning position by forward movement and stopped isintended to travel to the next movement path 500 by reverse movement.Thus, the output information control unit 146 displays characterinformation that instructs the driver to shift the movable portion inthe gear shift operation unit 7 into the R-range in the second displayregion 206.

FIG. 12 is a diagram illustrating an example of the screen 12 a of thedisplay device 12, which is displayed when the vehicle 1 travels towarda stop target P as a parking completed position. As illustrated in FIG.12, when the vehicle 1 travels toward the stop target P as the parkingcompleted position, the output information control unit 146 displays astop mark 204 b as the instruction mark 204. The stop mark 204 b is anexample of the first mark. The stop mark 204 b has a shape differentfrom that of the temporary stop mark 204 a. The stop mark 204 b may havethe same shape as that of the temporary stop mark 204 a as long as, forexample, the stop mark 204 b is different in color or size from thetemporary stop mark 204 a.

FIG. 13 is a diagram illustrating an example of the screen 12 a of thedisplay device 12, which is displayed when the vehicle 1 arrives at thestop region 501 including the stop target P as the parking completedposition. As illustrated in FIG. 13, the output information control unit146 displays the instruction mark 204 brightly on the screen 12 a of thedisplay device 12 when the vehicle 1 enters the stop region 501including the stop target P as the parking completed position.

When it is determined that the vehicle 1 has entered the stop region 501including the stop target P as the parking completed position, theguidance control unit 148 finishes the control of the steering unit 4via the steering system 13. The output information control unit 146changes the character information in the second display region 206 to“ASSISTANCE FINISHED”. Even after the control of the steering unit 4 bythe guidance control unit 148 is finished, the output informationcontrol unit 146 displays the stop mark 204 b on the screen 12 a of thedisplay device 12. The driver can refer to the display form of the stopmark 204 b (red with increased tone, or orange with increased tone orreduced tone) to operate the braking operation unit 6, thereby stoppingthe vehicle 1 at a desired position.

In the above-mentioned embodiment, the output information control unit146 controls the display device 12 to display the instruction mark 204that instructs the driver to stop the vehicle. The output informationcontrol unit 146 further controls the display device 12 to display theinstruction mark 204 in the display form in which the instruction mark204 is displayed brightly when the vehicle 1 is located within the stopregion 501 including the stop target P, and display the instruction mark204 in the display form in which the instruction mark 204 is displayeddarkly when the vehicle 1 is located outside the stop region 501. Inthis manner, the output information control unit 146 displays theinstruction mark 204 even when the vehicle 1 is located outside the stopregion 501, and changes the display form of the instruction mark 204when the vehicle 1 arrives at the stop region 501. Consequently, thedriver can know in advance by the instruction mark 204 that the vehicle1 needs to be stopped, and can stop the vehicle 1 in the stop region 501more smoothly. Furthermore, the driver can more clearly recognize thatthe vehicle 1 is located within the stop region 501.

The output information control unit 146 controls the display device 12to display the indicator 205 that changes in accordance with theposition of the vehicle 1. Consequently, the driver can recognize thedistance to the stop target P by the indicator 205 to stop the vehicle 1in the stop region 501 more smoothly.

The indicator 205 indicates the direction corresponding to the traveldirection of the vehicle 1. The output information control unit 146controls the display device 12 to dispose the instruction mark 204 inthe direction indicated by the indicator 205 with respect to theindicator 205. Consequently, the driver can more intuitively recognizethe distance to the stop target P by the indicator 205 to stop thevehicle 1 in the stop region 501 more smoothly.

The output information control unit 146 controls the display device 12to display the stop mark 204b when the vehicle 1 travels toward the stoptarget P as the parking completed position and display the temporarystop mark 204 a when the vehicle 1 travels toward the stop target P asthe turning position. This configuration enables the driver to know inadvance that the vehicle 1 needs to be moved to the stop target P as theparking completed position after the vehicle 1 is stopped in the stopregion 501 including the stop target P as the turning position.Consequently, the driver can drive the vehicle more smoothly toward thestop target P as the parking completed position.

The output information control unit 146 controls the display device 12such that the display form of the instruction mark 204 when the vehicle1 is located in the stop target region 502 and the display form of theinstruction mark 204 when the vehicle 1 is located in the stop availableregion 503 are different from each other. Consequently, the driver canrecognize a more proper stop target region 502 to stop the vehicle 1more smoothly.

The instruction screen 200 in the above-mentioned embodiment is merelyan example. For example, the output information control unit 146 maymove the instruction mark 204 in accordance with the distance betweenthe vehicle 1 and the stop target P. In addition, the temporary stopmark 204 a and the stop mark 204 b may be displayed at differentpositions.

The display unit on which the instruction screen 200 is displayed is notlimited to the display device 12. For example, the output informationcontrol unit 146 may display the instruction screen 200 on the displaydevice 8 in the monitor device 11, or may display the instruction screen200 on a windshield of the vehicle 1 by projection.

The above-mentioned embodiment of the present invention is not intendedto limit the scope of the invention, but is merely an example includedin the scope of the invention. An embodiment of the present inventionmay be subject to changes, omissions, and additions of, for example, atleast part of specific purposes, structures, shapes, actions, andeffects of the above-mentioned embodiment within the range not departingfrom the gist of the invention.

1. A driving assistance device, comprising: a target setting unitconfigured to set a stop target; an acquisition unit configured toacquire a position of a vehicle; and an output information control unitconfigured to control a display unit to display a first image thatinstructs a driver to stop the vehicle in a first form when the vehicleis located within a region including the stop target and display thefirst image in a second form different from the first form when thevehicle is located outside the region.
 2. The driving assistance deviceaccording to claim 1, wherein the output information control unitcontrols the display unit to display a second image that changes inaccordance with the position of the vehicle.
 3. The driving assistancedevice according to claim 2, wherein the second image indicates adirection corresponding to a travel direction of the vehicle, and theoutput information control unit controls the display unit to dispose thefirst image in the direction indicated by the second image with respectto the second image.
 4. The driving assistance device according to claim1, wherein the stop target comprises a first target and a second targetthat is provided in a middle of a path for guiding the vehicle to thefirst target, the first image comprises a first mark and a second markdifferent from the first mark, and the output information control unitcontrols the display unit to display the first mark when the vehicletravels toward the first target and display the second mark when thevehicle travels toward the second target.
 5. The driving assistancedevice according to claim 2, wherein the output information control unitcontrols the display unit to display the second image in the second formwhen the vehicle is located within the region and display the secondimage in the first form when the vehicle is located outside the region.6. The driving assistance device according to claim 2, wherein theoutput information control unit controls the display unit to display thefirst image or the second image brightly in the first form and displaythe first image or the second image darkly in the second form.
 7. Adriving assistance system, comprising: a target setting unit configuredto set a stop target; an acquisition unit configured to acquire aposition of a vehicle; and a display unit configured to display a firstimage that instructs a driver to stop the vehicle in a first form whenthe vehicle is located within a region including the stop target anddisplay the first image in a second form different from the first formwhen the vehicle is located outside the region.